Device for varying the strength of the type impression in typewriting office machines



1938- ;A. SALZBERGER DEVICE FOR VARYI'NG THE STRENGTH OF THE T IMPRESSION IN TYPEWRITING OFFICE MACHINE Filed Nov. 26, 1957 5 YPE s Sheets-Sheet 1 Oct. 25, 1938. A. SALZBER 2,134,343

I DEVICE FOR VARYING MPRESSION TN TYP Filed GER v NGTH OF THE TYPE I I OFFICE-MACHINES v 1937 3-Sheets-Sheec [2 THE STRE EWRITING- gfi Oct. 25, 1938. A. SALZB ERGER 1 2,134,343

- v DEVICE FOR VARYING THE STRENGTH OF TYPE Y i V IMPRESSIO N IN TYPEWRITING OFFICE M INES Filed Nov. 26, 1937 I 3 Sheets-Sheet 5 Patented Oct. 25, 1938 THE TYPE IMPBESSION 1N OFFICE MACHINES TYPEWRITING Andreas Salzberger, Erfnrt, Germany, assignorto' Olympia Buromaschlnenwerke A. G.,- Erfurt,

Germany Application November 26, 1937, Serial no. 176,746

In'Germany December 11, 1936 '1 Claims. (01. 191-449) With machines with noise-dampened type impression, especially with machines having a rigid type impression point, in which there'are, thus, .no elastic type levers able'to oscillate beyond the end position proper or no yielding intermediate members between the writing surface of the types and the surface receiving the impressions, it is indispensably requisite to provide means rendering it possible to adjust or re-adjust the platen in the direction of the type impression.

The known devices for the object in view must be selectively adjusted with the aid of an operating grip, may be manually with the aid of a graduated scale, which necessitates a certain amount of consideration and attention and includes the possibility of faculty adjustments, which can entail undesired efiects in that either obscure imprints or an insufficient number of copies or, perhaps, no imprints and, therefore, also no copies at all are obtained. If the adjustment is in error in the opposite sense and does not provide a platen position appropriate for a thick layer of paperythe imprint will be unduly strong as the type will strike the paper too forcefully, and this places an unnecessary burden on the mechanism of the machine.

It has already been endeavored to obviate the above-mentioned drawbacks by the provision of a touching member'which when held in contact with the paper, ascertains the thickness of the same and readjusts the platen automatically, for

instance by the intermediary of a rack and a pinion. But also this arrangement suffers from a drawback consisting therein thatthe entire readjusting resistance which increases considerably with the breadth and the weight of the platen slide must be overcome by the rods. The readjustment is subject to checkings and delicate workis, therefore, not possible, and the strong pressing-on pressure, or theadjustmentpressure respectively, makes it difficult to intro- I duoe larger piles of paper, if at all, and there exists also the danger of marking, that is to say, the pressure which the touching member exerts becomes visible on the copies through the carbonized sheets. 7

Now, the object of the present invention is to provide a device which requires for the adjustment of the platen only a slight pressure adapted to be accommodated to the introduction of the paper and to the feeling actionv of the touching member. The object in view is attained by means of a feeling or touching member co-op- U crating with a releasable auxiliary power holdj ing the platen in its readjusted position and merely preparing or initiating the readjustment without itself shifting the platen. I'he arrangement is preferably so that the auxiliary power is designed as a power accumulator, for instance an elasticity accumulator, which can'be thrown into'and outof' action by means of a gripalso 1 otherwise to be'used'when the machine is operated, which grip can be, for instance, the releasing grip for the lower paper guiding member, and in order. to simplify-the arrangement the devices to'be actuated bysaid grip may be so designed that successively first said lower paper guiding -member is released then the platenis withdrawn from its working condition, andflnally the member directly effecting the read justment of the platen is moved into its initial position, whereas on the return way said threeoperations are repeated in the reverse succession. Value isalso placed upon the possibility of shifting theplatenwithin the platen slide frame so as to obviate' shifting it together wtih the slide frame which constitutes a checking weight. The invention is illustrated diagrammatically and by way of example on the accompanying drawings on which Figure 1 is a transverse section through the lower paper guide members,

combined with a pressing-on roller serving as touching member. Figure'2 is a side-view of the adjusting rods for the platen; Figure 2a shows a modified constructional form of the upper half of Fig. 2 and Figure 3 illustrates likewise in side view thejreleasing drive for. the lower paper ,guide'me'mbers, combined with the device for withdrawing the platen.

The paperguiding device chosen by way of example and being illustrated in Fig. 1 is located below the platen l and consists of a front and a rear sheet-metal plate, of which the front plate is secured to an arm 2, whereas the rear plate is hinged to an arm 3; This rear plate is, besides, turnably suspended from a bolt 4 located inthe slide frame.

plates are provided with the usual recesses or Said paper guiding sheet-metal .slots through which the paper guidingrolls 5 and 6 pass. Each of these rolls is supported on an axle supported in turn by the extreme ends of ing counter to the respective arm, as in Fig. 1,v

the lug 3a being located below the lug 2a. The shaft 1 is supportedin the frame of the paper ,slide. Betweenthe' two lugs is a releasing shaft 8 which is provided with two transverse recesses which receive the said lugs, as shown; 9 denotestransverse slot a a running rail which is screwed to the bottom face of the slide frame Hi. I abstain from entering into details concerning said rail, as it does not pertain to the invention proper.

Between the two paper guiding rollers I and I is provided a third or additional roller ll (Figs. 1 and 2) which is the pressing on rollers and is supported in the middle portion of the longer arm l2 (Fig. 2) of a bell-crank lever attached by means of a bolt l3 to the slide frame. At the free end of said bell-crank lever arm is a pin i4 engaging an oblong hole lid of a vertical rod l5 connected with the said lever arm by a helical tensile spring l6 (Fig. 2). The pin, I4 is nor-- mally held by said spring in. the upper end of said hole. Also the shorter arm i2a. of the bellcrank lever is subjected to the action of a heli-' cal tension spring I! whereby the roller i I is con tinually held in contact with the platen I. The shaft 8 has not only the two transverse slots receiving the lugs 2a and 34, but there is in it a third 8a receiving the lever arm i2a, as in Fig. 2. v

Above the axle 24 of the platen l is aldoublearmed lever .i! which is supported on a bolt l9 screwed into the slide frame. The lever i8 is connected at one end withthe vertical rod l5 and at the other end with a wedgeshaped slide 20 guided in a guide member 2| affixed to the slide frame.

Instead of. said wedge-shaped membern an eccentric disk 20a (Fig. 20.) may be used. This disk is supported on a bolt 22 likewise screwed into the slide frame and is connected with the lever I8 by means of a link 23. The effect of this arrangement is the same as with the example shown in Fig. 2.

The axis of the platen I is encompassed by a sliding bearing 25 which can be shifted in an oblong aperture 26 (indicated by dotted lines in Figs.

2 and 3). provided in the platen slide frame. On the side opposite the wedge-shaped member 20, the oblique face of which is located opposite the sliding bearing 25, this latter has likewise an oblique lateral face, the obliquity 'of which corresponds with the obliquity of theinclined face of.

the member 20,.as shown in Fig. 2.

The sliding bearing 25 of the platen axle is I provided with a flange-28 from which projects a lug 28a connected by a pivot 28b with the arm 29a of a bell-crank lever 29 which is supported on a bolt 30 supported in turn in the slide frame. The upper end of said lever arm is connected with a comparatively strong helical tensile spring 3|, the other end of which is aflixed to said frame. The other arm (29b) of the bell-crank lever contacts at its free end with a. cam32 secured to the shaft 8 provided, besides, with a toothed segment 33 meshing with another tcothedsegment'fla forming the lower end of a double-armed lever 34, the other arm of which projects upwardly (Fig. 3) and constitutes a manually operable grip. Below the toothed segment 33 is a crooked arm 35 which serves for the changing-over of the, as

tion and I therefore do not enter into details concerning them. I emphasize, however, that as regards the readjustment of the platen, it is important to abstain fromchanging the position of the guide rail for the said outer slide-frame in that this rail is of. fundamental value for several operations which will be dealth with hereinafter. The manner of operation of the device is as follows:

When the sheet to be written upon has been introduced into the machine it depresses the pressing-on roller corresponding to the thickness .of the paper and turns thereby the bell-crank lever i2 (Fig. 2) on its bolt i3.' The pin it which is located at the free end of the longer arm of said lever and engages the oblong hole lid of the rod I5 is moved downwardly in said hole and simultaneously'therewith the springs l6 and I1 are correspondingly tensioned.

Now the'grip 34 (Fig. 3) which is generally used.

for straightening the sheet shoved into the machine until having arrived at the place of writing is swung forwardly from the position shown in full lines to the position shown' in dotted lines whereby-the toothed segments 34a and, 33 are turned by about 90, as is also the shaft 8. This causes three successive operations, viz:

(a) The shaft 8 releases the lower paper guidshaft I presses against the arm 29b'of'the bellcrank lever 29 (Fig. 3) and turns it counter to the pullof the spring 3i whereby the arm 29a of said lever draws the platen forwardly into an end position, or a position of rest respectively,

by the intermediary of the members 282:, 28a and 28 and whereby at the same time ,the wedge 20 (Fig. 2) is released from the action of the member 21 so that itcan be lifted by the lever l8 and the rod i5 by the pull of the spring l6. Simultaneously therewith the pin i4 reassumes its original position in the upper portion or end of the hole |5a of the rod l5.

'(c) The downwardly directed short arm I2a (Fig. 2) of the bell-crank lever I2 which arm engages a transverse slot of the shaft 8,'is turned by this shaft counter to-the pull of the spring I! whereby the lever arm i 2 islifted beyond its usual adjusted position and moves, in turn, under the pull of the spring It, the members l5, l8 and 20 into their end position.

When the grip 34 is being moved back into its original position, after the straightening of the sheet of paper relatively to the place of writing,

all members having been actuated when said grip had been swung into the position shown in dotted lines in Fig. 3 get now back into their former position in the reverse succession. The

(Fig. 2) 'which corresponds to the thickness of the sheet of paper introduced into the machine. The tensile spring 3| draws the sliding bearing 21 firmly against the oppositely located oblique face of the wedge 20 and retains this in its position whereby an unintended change of the position in the platen is securely prevented. Finally,

the lower paper guiding member is. again laid against the platen. f

1 Finally, concerning the entire arrangement and combination of theparts shown and described, it'is to be noted that the rods and arms and levers shown in Figs. 2 and 3 are to be provided at both sides of the machine, that is to say, symmetrically, in an inconspicuously manarses ner, and as regards especially the feeling or touching roller i I it is suited to the purpose in view to subdivide it or, in other words, to provide several such rollers (co-axially) and distribute the individual parts or rollers along the platen.

What I claim as new and desire so secured by Letters Patent of the United States is:

1. In a typewriting machine, the combination with a' platen, and means supporting said platen for movement to vary the strength oi the type impression, of power means for moving said platen towards one end position of adjustment, an adjustable stop for limiting movement of the platen by said power means, means operable manually to displace said platen from said stop in opposition to said power means, and setting means operable manually to displace said platen from said stop, a feelerfor contacting the impression sheets carried by the platen, and means actuated by said ieeler in the interval between movement of the platen in opposite directions bysaid manually operable means and said yielding means for setting said stop in accordance with the thickness of the impression sheets.

3. In a typewriting machine, the combination with a platen, means supporting said platen for movement to vary the strength of the type impression, rollers for holding impression sheets to said platen, and means manually operable to displace said rollers to facilitate adjustment oi the impression sheets on said platen; of means operable by said manually operable means, when actuated to displace said rollers, to adjust said platen to a position appropriate for the impression sheets carried by the platen, said last means including a feeler for contacting the impression sheets. v

4. The invention as claimed in claim 3, wherein said platen adjusting means includes spring means yieldingly urginglsaid platen in one di- 'rection, stopmeans ,for limiting such movement. means controlledby said feeler for setting said stop means, said setting means being inoperative when said platen is held to "said stop means by said spring means, and means actuated by said manually operable means to displace said platen from said stop means, thereby to render said setting means operative.

5. In a typewriting machine, a platen, means supporting said platen for movement to vary the strength of the type impression, stop means for determining the position of said platen, spring means normally retaining said platen in the position determined-by said stop, and manually operable means for displacing said platen in opposition to said spring means and resetting the f stop means, said manually operable means including a feeler contacting the impressionsheets carried by said platen. I

6. In a typewriting machine, 'a carriage, a

' platen, means supporting said platen for movement to vary the strength of the'type impression, spring means tending to displace said platen into the end position corresponding to maximum pa-, per thickness, cooperating stop members on said ment of said platen by said spring means, means tending to displace the stop member of the carriage into a position corresponding to maximum paper thickness, said last means being inoperative to displace its associated stop member so long as said stop membersare'held'in engagement by said spring means, a feeler yieldingly contacting the paper'and limiting displacement of the carriage stop member, and means oper-.

I able manually to perform the cycle of displacing said platen into inoperative position in opposition to theforce of said spring means, moving said ieeler away from the platen, releasing the feeler to permit its return to contact with the paper,

mamas sanznsaana.

as platen and carriage for limiting the displacev 

